


Watching You Walk Away

by Erin Silverlight-Rey (SilverMillenium_QueenNeptune)



Category: Shadowhunters (TV)
Genre: Alternate Universe - Canon Divergence, Bottom Alec Lightwood, Eventual Sex, Eventual Smut, Gay Sex, Implied/Referenced Drug Use, Isabelle Lightwood Deserves Nice Things, Light BDSM, Light Bondage, Light Masochism, Long Live Feedback Comment Project, Multi, References to Addiction, Supportive Isabelle Lightwood, Switch Isabelle Lightwood, Switch Simon Lewis, Top Magnus Bane, Vampire Simon Lewis, Yin Fen
Language: English
Status: In-Progress
Published: 2019-02-17
Updated: 2019-06-05
Packaged: 2019-10-30 01:28:11
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 3,729
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17819225
Author URL: https://archiveofourown.org/users/SilverMillenium_QueenNeptune/pseuds/Erin%20Silverlight-Rey
Summary: Rated for later content with TW for references to Isabelle's drug addiction to yin fen and a relapse. When Alec and Magnus decide to abstain from sex for a while, Isabelle is supportive but knows something is wrong.  She resolves to help the couple get the spark  back in their relationship. Unfortunately, the desperation she feels opens an old wound she thought had been long closed, and her addiction to yin fen rears its ugly head again. She goes to the only vampire she can trust, but doesn't realize Simon wants to give her so much more than his venom. Belated Valentine's fic. Chapters are a guess at this point.





	1. Moments Like This

**Author's Note:**

  * For [dmichelle312](https://archiveofourown.org/users/dmichelle312/gifts).



> This story is part of the LLF Comment Project, which was created to improve communication between readers and authors. This author invites and appreciates feedback, including:
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Magnus Bane loved every second of being close to his Shadowhunter boyfriend. As soon as Alec had walked through the door, Magnus had gripped his collar tightly, teasing his free hand over the fabric. 

"My Alexander.", he breathed. Alec's hair stood on end at the words. His name dripping off Magnus' lips, being held against him like this. . . he knew exactly what Magnus wanted, and he would be all too happy to give it to him. Magnus bit his lip, imagining Alec's face as he held him down. 

"Magnus, please.", Alec whispered. He hated being teased. He struggled, and Magnus let him go.  He wanted to see if the Shadowhunter would leave. But he knew the answer already. Alec turned, and Magnus could half see his brown eyes close. He was anticipating something. Perhaps he wanted to be chased. He gave him a look, and before he knew it, Alec was coming back to him. Magnus smiled. 

"Can't leave, Alexander?"

"No. Of course not. I realized, I've got time. We could. . .", Alec began, nuzzling into Magnus' skin. He nipped at his collarbone, and Magnus' eyes flashed. 

"Alexander, don't. Not unless you know what you're starting."

"Believe me, I do.", Alec nearly purred.  The perk of dating a Shadowhunter, Magnus supposed, was that his boyfriend only kept him guessing, and he loved it.   But he knew they needed to slow down. He didn't want to lose the spark between them.  He didn't want to give in so easily. He took a breath, steadied himself. 

"Magnus, I'm sorry. So sorry. I don't mean to be a tease. But I. . . I need to get back to the Institute." It was an excuse. He knew that. He wouldn't have admitted it, of course. But Magnus knew he was a Lightwood, and a Shadowhunter. He knew what he had signed up for when he'd agreed to date the stubborn angel-blooded warrior.

"Come back to me. You owe me, and I intend to finish. Be careful. I love you."

"I hear you, Magnus. Loud and clear. I love you, too. Are you angry?"

"Not at all. I knew what I was getting into when I fell for a Shadowhunter. Besides, I _love_ the view I get watching you walk away."

"Oh, behave, you dirty boy!" Alec laughed, and soon he was gone. Magnus snapped his fingers and his clothing went back to normal. If a customer showed up and could tell what he had been about to do, it would be a disaster. 


	2. Powerless

**Summary for the Chapter:**

> Isabelle retreats, and Alec knows something is wrong with his baby sister. This chapter contains a TW for mentions of drug use, due to the classification of yin fen. Also, Alec worries about his connections with Magnus and Jace.

Isabelle's hands were shaking as she finished readying herself for the day. Somehow she'd managed to steady them long enough to put on her makeup and put on one of her favorite dresses and pairs of boots. At her mother's request, Isabelle's outfit showed surprisingly little skin and was unexpectedly conservative. She knew she would never hear the end of it from her mother if she didn't comply with this one issue. She smiled to herself in the mirror as she finished off her look by brushing out her dark hair and applying a deep red lipstick. 

"There. Now I look presentable. At last.", she sighed as she fixed her winged eyeliner where an unsteady hand had smudged it.  She opened her drawer, making sure the door to her room was locked before she grasped a small tin hidden inside. She only needed a little, and then she would be fine again. She told herself that every morning.  It was never true.  It hadn't been for a long, long time. 

"By the Angel, it's all gone again.", she swore softly. She couldn't go back to Aldertree for more. Isabelle may have been addicted to yin fen, but she wasn't stupid, and she knew Aldertree would hold the addiction over her head. The thought of the indecent suggestions he'd made to her in return for his "help" made Isabelle's skin crawl.  She'd never felt comfortable around him, but he had been the first to offer a solution, even if his method was sleazy. Every now and again the memories of her wounds came back, and when they did, the phantom pain was too much for her.  It had been a month since she'd sought venom again, she realized. She'd become so desperate that Rafael had ordered his clan not to give her any venom. Rafael himself had been Isabelle's link to venom once upon a time, but that had ended a long time ago. They'd argued about how Isabelle was using him. It was unfortunate, since they had been getting close before the fight. 

Isabelle might have even thought she was falling in love with him. There was nothing wrong with a Shadowhunter and a Downworlder falling in love. She had a past intimate relationship with a Seelie. Clary was friends with and protected by a warlock, a werewolf and a vampire. The warlock was also her older brother's partner, and the two were deeply in love.  But her own relationship with Rafael, well, that was a different story. Yin fen, and Isabelle's desperate need for it then, had put her, Rafael, and the entire Shadow World's peace in danger. Isabelle had become unfocused.  Her mind corrected itself then. Clary  _had been_ friends with them, and now. . . now, she was being mourned. She was gone. Isabelle had the second chance that Clary didn't. 

 _That settles it, then. Going back to Rafael is out. I cannot put him at risk._ Isabelle had gotten to know Rafael, well enough to know that they would never work. He'd always felt guilty for feeding from her. But the last thing she wanted or needed was the baggage that came with things getting complicated. She could not go back to him and make him compromise himself. He had never become adjusted to the idea of feeding on the  blood of a Nephilim warrior.  He couldn't bring himself to let her become tainted by him. Shadowhunters existed for a reason. The angel wouldn't have created them with pure angelic blood if there hadn't been some sort of purpose for it. She never even noticed Alec walking past her.  She knew going back to using yin fen was risky. But this pain. . . she needed to find some way to deal with it. If she didn't, she was completely powerless. 

* * *

Alec knew something was wrong with his baby sister. He didn't want to say anything directly to her. But he knew Isabelle well enough to know she wasn't herself.  He'd noticed the way she tugged at her jacket. Though she'd begun dressing more conservatively to appease their parents, Alec was worried that there was more to Isabelle's clothing choices lately. She was barely making eye contact. She appeared shaky and less confident. He'd been well aware that she had struggled with yin fen in the past, but she was clean now, wasn't she? Of course she was. Besides, they had more important things to focus on.  Alec was distracted enough as it was. 

Ever since Clary had disappeared, Magnus had been despondent. Alec had tried to go and see him, but Magnus wouldn't even answer the door. All the runes and power the Angel had granted him couldn't help him understand why he was being shut out like this.  He wanted to try to go back, talk some sense into Magnus, let the warlock bind him in chains and use him as an outlet if necessary... 

The thought made him blush. Before all of this, they had talked about "expanding horizons", as Magnus had called it then. Alec hadn't known what he'd meant, but he was confident that no matter what, he would be safe. Magnus loved him. He would never hurt him.  He knew that. But right now, Magnus was focused on finding Clary's body, and Alec's world was falling apart.  

It was no secret that he had never really gotten close to Clary, though it was clear to him that she was very important to those around him; Isabelle, who had befriended the novice Shadowhunter, and Jace.  He'd tried to tolerate her, for Jace's sake. Some days it had been difficult, but he reminded himself that Jace loved Clary.  Now she was gone. 

 _Jace._ His parabatai. The most important person in the world to both Alec and Clary. If anyone loved Jace as deeply as Alec had, and more, it was Clary. No matter how Alec felt about her, he knew that. He could feel Jace's pain, knew he wished for death. The thought caused him to suppress a scream.  Jace and Alec's bond had been tested by the discovery of Isabelle's addiction and helping her beat it, and now they had been through much more than either had imagined. Jace's mind had been taken over by Lilith for a time. Somehow, though, he had broken free. Even so, Alec could see and feel the emotional scars left behind. Now, Lilith had her son, and Clary was gone. Jace was in mourning and Isabelle was. . . well, God knew what was going on with Isabelle.    

This whole situation scared him. If Lilith could get to Clary, had the power to manipulate those around him. . . then was he in more danger than he knew? What about Magnus? The thought of losing Magnus had crept into his mind, though he had tried to push them back. He swallowed hard, clenched his fist. Tried to push the image from his mind. He couldn't lose Magnus. Neither of them would let it happen.  But with the Institute occupied with searching for Lillith and Jonathan, finding whatever trace of Clary was left to give her a proper Shadowhunter farewell. . . he hadn't had the time. Even if he had, Magnus had hardly been in the mood for intimacy. He'd spent a long time protecting the Fairchild women. 

 _Magnus. I need to go to Magnus. We need to talk. He knows what I'm going through. He'll help._ Alec didn't want to admit how much he had gotten scared by Clary's death. It had reminded him that time was short, and even if Magnus was immortal, neither of them was invulnerable. Every moment counted for them. He could not let himself feel this powerless forever. If only he had been able to see Isabelle at that moment, he would have known he was not alone.


	3. Slippin'

**Summary for the Chapter:**

> Tasked with checking on Simon to see if he has heard anything through the Downworld grapevine lately, Isabelle offhandedly makes a remark that concerns the Vampire. Alec begins to notice something is wrong, and confides in Magnus.

**Notes for the Chapter:**

> Hey, everyone. So I know a lot of people don't read author's notes but I want to make something clear. At the point in time that this fic is written, Isabelle is _already_ battling her addiction to vampire venom, aka yin fen in the Shadowhunters universe. She is only going to Simon instead of Rafael because he has realized they were using each other and cut her off. She has gone to Rafael for venom before the start of this fic. If you go back and read the first chapter you'll notice where I mention via Izzy's internal monologue that she can't tempt Rafael like that again. She believes Simon's willpower is stronger-- but she did still go to Rafael initially, and for quite a while.

Alec reclined in his chair and attempted to breathe for a moment before the chaos descended. He'd had a morning of pure bliss with Magnus, but even he had known something was off, and his cat-eyed warlock was worried about something. Still, it frustrated him that whatever it was, Magnus wasn't ready to open up and tell him. All he had said was that he'd overstepped. But Alec knew when Magnus was walking on eggshells. He'd seen it when they'd invited his mother over for dinner after she had been de-runed. 

They'd had different worries then. Things had been calmer, and the world as they knew it wasn't in chaos. Alec had to laugh at his mental picture of the situation. Their worlds had been chaotic from day one, whether he chose to admit it or not. With Clary gone, many of those closest to him had lost a friend, a family member, and an ally. He hoped she had been united with her mother again, but he had no way of knowing.  He knew that if it were him, and his mother had been gone as long as Clary's, he'd want to be wherever she was. He thought about Luke, and how much the Shadowhunter turned werewolf pack leader missed both women. A blind man could have seen that even when he was Lucian Greymark, he had been in love with Jocelyn Fairchild.  He had raised Clary like a daughter of his own, looked out for her, taken care of her and her mother, and now they were both gone. 

Magnus had been close to Clary too. He'd been a friend to Jocelyn, wiped Clary's memories of the Shadow World as a child, and protected her. She was important to him.  Alec understood, but he couldn't get over the fact that she was Valentine's daughter.  He had been trying, for Magnus' sake, and for Jace's.  He knew that those around him who were close to Clary would need him. If he were being honest, she had grown on him. Clary was growing as a Shadowhunter. He had been hesitant to accept her, but she was one of them. Clary had proven herself, and Jocelyn had died in honor some time ago.  Even if Clary's father had been misguided, she had proven herself over and over. So Alec didn't know how to feel. He had busied himself at his desk when his sister walked into the room. 

Instantly, Alec noticed the difference in the way she was dressed. Though Isabelle normally showed off her figure in colorful clothes, today she was much more conservative. She had only dressed this way before to appease their mother and father when they visited the Institute, and that didn't happen anymore. Maryse Lightwood was no longer a Shadowhunter, de-runed for her role in the Circle and Valentine's uprising and Robert had not visited since Maryse had divorced him, choosing instead to remain in exile in Idris. Alec knew the decision had an impact on both he and Izzy. Though she hadn't initially seemed bothered, Isabelle had changed lately, avoiding him and shortening conversations. She spent extended time in the weapons room, and rarely volunteered for Shadowhunter missions. 

 _Something's wrong with Izzy. I wish I could tell what it was._ But try as he might, Alec couldn't find a way into his sister's mind. Even if that was an ability that the Angel had seen fit to grant, Alec knew that looking into his sister's mind might not give him the answers he hoped for. He also knew that Isabelle had struggled to find her place again, though why she seemed to devalue herself, he had no idea. She was smart, beautiful and headstrong. She was a Lightwood, and if anyone knew how to overcome adversity, it would be Isabelle.  He needed to support her.  But what was the best way he could do that?u

"Did you need something, Iz?", he asked, wincing when she avoided his gaze. .

"Uh-- no. Not really. I just. . . Um, I wondered if maybe you needed me to. . .", she stuttered. She was never this nervous, and especially not around him.  What was going on with her?

"The only mission we have right now is finding Jonathan. Did you check with anyone about the Downworld  news yet? Maybe Simon knows something. Or perhaps Meliorn would be willing to help, if you asked."

"No, I haven't. I could go find Magnus or Lorenzo, see what they know. Unless you think that's a bad idea?"

"Going to Magnus right now might not be the best. He's been pretty broken up since Clary vanished. Check with Simon. There's a chance Lorenzo might know something, too. Depends on the kind of mood he's in as to whether or not he'd help us, though.", Alec mused.  Maybe they could beg, tell Lorenzo what a valued member of their community Clary was. . . but she was also Valentine's daughter. Perhaps the Downworld would believe they were better off to be rid of her. 

"Simon, then. He's close to her. I could also speak to Luke, see if the wolves might help since he's the closest thing she had to a father."  That was true, Luke had been there for her. He had loved her and Jocelyn, treated them like his family. He had helped to protect her from the Shadow World even when she hadn't known it existed. If it had not been for Luke, Clary might have been a lot less safe. As she thought of it, Isabelle winced. Simon, Luke, Magnus, Jace. . . all of them close to her and all hurting in their own ways. What could she do to help?

_Nothing. I can't bring her back. There's nothing I can say. All I can do is pray to the Angel that Jonathan hasn't decided she's outlived her usefulness yet, and killed her. Because if he has, then our world is upside down. I can't let this be the end of her story. It might be that she is the only one who can save us all. I only hope we aren't running out of time._

* * *

Simon was still amazed at his abilities, even now. Walking in the sunlight was something he'd never expected to be able to do again when he became a vampire. Daylighters were special, he'd realized, and the uniqueness of his powers had cost him friendships or caused jealousy. Still, he didn't have the one thing he had always wanted.  Someone to love him, and care about his immortal existence. He still had his family, but they were far away. The last thing he needed was for Heidi to return and try to make a meal of them again. With his luck, he'd anger another vampire and then he would be concerned all over again. Would this one know how to track his sister or his mom? It was a risk he couldn't take. If it meant they were safe, he was happy to be alone.

He was staring up at the sky when someone called his name. The voice carried, but even with his enhanced hearing, Simon wondered for a split second if he could be dreaming. The owner of the voice couldn't be the one person he wanted it to be. Clary was gone. He turned and immediately met a pair of worried brown eyes.

"Hi, Simon. We need your help."

"Sure. Name it, whatever you need.", he said hurriedly. Simon always seemed willing to help or do whatever the Shadowhunters had asked, especially Clary. Isabelle knew the loss would hit him hard.  Maybe he needed a way to distract himself. Simon and Clary would probably be parabatai if Simon ever was able to become a Shadowhunter. Maybe that was why they'd never been able to make a relationship work. Simon often wondered what it would be like to be a Shadowhunter, but he didn't think he'd get the chance. Or maybe. . .   
Isabelle broke into his thoughts.

"We need you to keep ears out among the vampires. If you hear anything about Lilith or Jonathan, let us know. It might lead to finding wherever Clary's body may be. We need to have her properly mourned and buried in the City of Bones."

"But can you? If she's with Jonathan, if she's helped him. . .", Simon trailed, not wanting to think about Clary being a traitor to the Shadowhunters. The Clary he knew had been good and uncorrupted. She'd tried to do the right thing. If anyone was meant to be an angelic blooded force for good, it was Clary Fray.  For the first time, he looked up at Isabelle and saw she was shaking. 

"I'm okay, Simon."

"No, you're not. You're in withdrawl, Izzy. I can see it.", he sighed, not knowing how to help.  But then she whispered something that would have made his heart stop, if it were still beating like any normal human's. 

"Just _one little bite_ would do the trick."

"No."

"What, I didn't. . ."

"No, Izzy. I won't do it. I  _can't_ do it. It's a violation of the Accords, you  _know_ that. You don't think that's what you're doing, but. . . Isabelle, it's all over your face. When was the last time you used yin fen?

"Not since. . .", the Shadowhunter paused, and thought about the question. She'd been shaking for days, maybe even weeks. As she tried to answer the question, she realized it had been a very long time. But if that were really true, then why was she still craving vampire venom? Why did she so desperately want to be bitten again? 

"Dunno. Look, Simon, I can't talk about this."

"We have to, because unfortunately, as much as the vampire clans are worried about Jonathan, they could care less if Clary's alive or dead.", Simon snapped, his voice breaking. The tears pulled Isabelle back into the reality of her mission. 

"Simon, I'm. . ."

" _Don't._ Don't patronize me by telling me you're sorry. You have no clue what Fray meant to me! If I'd really known anything, don't you think I'd be trying to save her by now?! You all are the ones that let Jonathan get close to her. If you hadn't she wouldn't be... God, I wish we'd never come to Pandemonium that night and met you!" Isabelle jerked away as though she'd been slapped, and Simon froze. 

"I- I'm sorry. Izzy, I'm so sorry. I didn't mean to-- the words came out before I--." Just like that, he crumpled to the sidewalk in a sobbing mess.

"Simon, it's okay. You miss her, and that's okay." She rubbed his back, and eventually the tears came to a shuddering stop. He wiped his eyes and frowned.

"Y'know, if I were a Shadowhunter, she probably would have been my--what do you call it, that bond that Alec and Jace have?"

"It's called a  _parabatai_. You're probably right, too."

"How come you don't have one?"

"Usually, if a Shadowhunter doesn't connect with a  _parabatai_ at a pretty young age, they never have one. That was me. I was always on my own. I envy Alec and Jace. But maybe I'm better this way."

"You could still find one, right?"

"Could. But chances are slim now."

"I'll keep an ear to the ground for you on Clary. The last I heard, Lilith has some pretty wild ways to stay out of sight. Something about a house that can move anywhere in the world with demonic magic. But that's all I know."

"Okay. Thanks."

"Izzy."

"Yeah, Simon?"

"Thanks. For doing right by Fray. For trying to bring her home. It's what she would've wanted. What her family would've wanted. If there's any chance she's still. . ."

". . . I'll bring her home safe." Isabelle's boots clicked as she walked away, and Simon fought off the urge to pull her back and taste the angelic blood singing in her veins. He hoped her desire for vampire venom wasn't as strong as his plea to find Clary. Because deep down he somehow knew that Isabelle had to be the one to bring his best friend home.

**Works inspired by this one:**

  * [Can't Remember To Forget You](https://archiveofourown.org/works/17977118) by [Erin Silverlight-Rey (SilverMillenium_QueenNeptune)](https://archiveofourown.org/users/SilverMillenium_QueenNeptune/pseuds/Erin%20Silverlight-Rey)




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